Thoughts on my current MS2 maps please

dbv8 · Post by **dbv8** » Tue Apr 09, 2013 8:47 am

Running well but looking for improvements (particularly in mpg at cruise).

TVR 4.6 rover V8 with big valve heads, real steel Typhoon cam, ported inlet, blended trumpet base. Full decat. Last dyno gave 275 RWHP.

Quagmire · Post by **Quagmire** » Tue Apr 09, 2013 12:13 pm

I can't help you at all, but a couple of questions:

What TPS % and rpm do you cruise at?

Whats your req fuel figure?

dbv8 · Post by **dbv8** » Tue Apr 09, 2013 12:32 pm

Quagmire wrote:I can't help you at all, but a couple of questions:

What TPS % and rpm do you cruise at?

Whats your req fuel figure?

On the motoway i can cruise between 15 and 20% TPS for 70 to 90 mph
With my new diff i run 30mph / 1000 rpm so 3000 = 90.

My req fuel figure is 7.7, I am considering lowering it to up the table scale.
What do you think?

Quagmire · Post by **Quagmire** » Wed Apr 10, 2013 12:15 pm

Ah, also meant to say - what flow rate are your injectors? Standard Range-Rover jobs or something more exotic?

dbv8 · Post by **dbv8** » Wed Apr 10, 2013 1:16 pm

Quagmire wrote:Ah, also meant to say - what flow rate are your injectors? Standard Range-Rover jobs or something more exotic?

I still run the standard TVR Bosch greens.
they are rated to 230cc or 22lb per minute at 40 psi = 2.7 bar.

My fuel was upgraded to a Bosch 044 pump and Weber Alpha regulator and now runs at 3 Bar.

dbv8 · Post by **dbv8** » Wed Apr 10, 2013 1:34 pm

I had a play last night tuning on the fly after adding advance in the cruise area of the ignition table. I still need to richen up full throttle but its set for the long drive home tomorrow night. Lets see what mpg i get.

Ignition table

Fuel table

dbv8 · Post by **dbv8** » Wed Apr 17, 2013 6:28 am

So i set off from Portsmouth last week with a full tank brimmed to 3 clicks.
I took it easy but maintained the 'normal' cruising speeds on the M27, A34,M40,M42 (inc Toll) and onto the M6. It was exactly 200 miles to Keele and took me (ahem) less than 3 hours.

I filled the tank in the same manner with just 31.5 litres = 28.8 mpg.

I got less than that out of my daily Mazda 323f on the way back down Sunday.

Quagmire · Post by **Quagmire** » Sun Apr 21, 2013 1:30 pm

Nice work! If only I could get my 3.5 powered 90 to get above 20mpg I would be happy. I suspect a leaky injector is not helping my cause, and need to add my timing at cruise like you have.

New (old) injectors next, and then further tweaking will commence.

DaveEFI · Post by **DaveEFI** » Sun Apr 21, 2013 2:25 pm

Out of interest, why are you using a Req Fuel setting so different from the calculated value?

dbv8 · Post by **dbv8** » Mon Apr 22, 2013 7:11 am

DaveEFI wrote:Out of interest, why are you using a Req Fuel setting so different from the calculated value?

Dont know Dave

Can you explain further please. I am a beginner to this.
I thought the required fuel figure was just a number to scale the map

Quagmire · Post by **Quagmire** » Mon Apr 22, 2013 7:20 am

From the ms3 pages:

REQ_FUEL

REQ_FUEL (short for "required fuel") is the part of the computation that tells MegaSquirt® how big your injectors are, and what your cylinder displacement (CYL_DISP) is. It is the length of time in milliseconds [ms] that MegaSquirt® should “squirt” to give the stoichiometric amount of fuel (14.7 Air/Fuel Ratio for gasoline) at 100% VE, a manifold absolute pressure (MAP) of 100kPa, and an air temperature of 70 degrees Fahrenheit for a complete stroke cycle.

As far as i understabd it if your dead time and reqfuel are correct you should in theory be ableto change injectors, input your new reqfuel and dead time figures and have no need to retune your ve tables.

But you are correct in saying that it is a multiplier. You can lower the reqfuel from the calculated figure to gain more resouktion in your be table.

dbv8 · Post by **dbv8** » Mon Apr 22, 2013 7:50 am

I dont understand Daves comment about the 'calculated value'.
What is this?

Quagmire · Post by **Quagmire** » Mon Apr 22, 2013 9:58 am

For any given setup there is a calculated req_fuel value. This is based on the flow rate of your injectors and the displacement of your engine (among other things).

Go here to calculate yours - you may need to scroll down a little:

http://www.megamanual.com/v22manual/mfuel.htm#reqfuel

I think tunerstudio has a built in req fuel calculator these days but may be wrong.

DaveEFI · Post by **DaveEFI** » Mon Apr 22, 2013 10:25 am

Quagmire wrote:For any given setup there is a calculated req_fuel value. This is based on the flow rate of your injectors and the displacement of your engine (among other things).

Go here to calculate yours - you may need to scroll down a little:

http://www.megamanual.com/v22manual/mfuel.htm#reqfuel

I think tunerstudio has a built in req fuel calculator these days but may be wrong.

Tuner Studio is the one to use these days as it's being actively developed/supported, and has had a Req Fuel calculator for ages. There is a free 'lite' version, but it's well worth paying the modest sum for the full one.

dbv8 · Post by **dbv8** » Mon Apr 22, 2013 12:02 pm

Oh i see now. I put in numbers that i think are right and got a figure of 16.7 (at 2.7 bar) maybe need only 15.3 for my 3 bar.
My required fuel according to MS is set at 7.7 ??

There must be something else thats out of wac then